Self-lubricating abutment



Nov. 26, 1968 I M. EUDIER 3,413,048

SELF-LUBRICATING ABUTMENT Filed July 26. 1966 United States Patent 27,22 1 Claim. c1. 308-160) ABSTRACT OF THE DISCLOSURE A self-lubricating abutment on a shaft has a porous sintered metal base having undulations passing through the axis of rotation and a layer of sintered microporous metal having a porosity below 1.3 microns covering the entire surface of the undulations.

The invention relates to a self-lubricating abutment for a shaft comprising a bearing surface perpendicular to the shaft axis and rotating in contact with the abutment.

It is well known that a self-lubricating metal made by sintering is a porous metal whose pores are generally filled with very pure mineral oil. Bearings made with a self-lubricating metal of this type are used in order to avoid periodic lubrication. However, these bearings often operate unsatisfactorily when the shaft is subjected to an axial load, i.e. thrust parallel to its axis, even if there is a collar to form an abutment on which a shoulder rigidly connected to the shaft bears. This is because there is no film of oil between the collar and the shoulder on the shaft.

The self-lubricating abutment according to the invention overcomes this disadvantage and is characterised in that it comprises facets forming undulations in which the directions of the edges of the highest and lowest parts of the undulation pass through the axis of the abutment.

The shoulder on the shaft therefore rests on an undulating self-lubricating surface, and experience has shown that such an abutment has a much longer life than conventional abutments.

FIGURE 1 is a perspective view of an abutment constructed according to the invention, the shaft and its shoulder being shown with dot-dash lines;

FIGURE 2 is a plan view of the abutment shown in FIGURE 1, with a supplementary ring around it; and

FIGURE 3 is a section on a larger scale on a line III III in FIGURE 2.

The abutment shown in the drawings consists of a collar 1 resting on a support 2 with a rotary shaft 3 passing through it and along its axis. The shaft is rigidly connected with a shoulder 4 bearing on the abutment collar 1.

According to the invention the surface of the abutment in contact with the shoulder 4 has radial undulations. The highest and lowest edges of the undulations pass through the axis of the abutment. The highest parts 5 take the load of the shoulder 4. On each side of these parts 5 there are facets 6, which are plane in the embodiment shown.

Rotation of the shoulder 4 relative to the abutment 1 causes oil to be sucked across some of the facets 6, viz.

3,413,048 Patented Nov. 26, 1968 the facets falling away from the shoulder 4 in the direction of rotation of this shoulder. The other facets, which rise towards the shoulder in the direction of rotation, cause an increase in pressure in the oil film, supporting the shoulder.

The abutment which has just been described may be fitted with a ring 8 (FIGURE 2) surrounding it and having a height h (FIGURE 1). This ring 8 prevents loss of oil because of centrifugal force. Although the height h is shown in FIGURE 1, the ring itself is omitted from the figure for the sake of clarity.

In these conditions the product of the initial load supported by the shaft in newtons/cm? multiplied by the speed in metres per second reaches the value of without any difficulty.

The abutment may be improved by providing the whole of the surface facing the shoulder 4 with a metal layer 9 having very small pores which are less than 1.3 (1.3 microns) in diameter and prevent air from passing because of the capillary forces of the metal. The oil film is then maintained completely without any loss of oil, and multiplication of the load by the speed always gives a value greater than 1,000.

Obviously, the invention is not restricted by the details of the embodiment just described. These details could be modified Without exceeding the scope of the invention, and the embodiment described has only been given by way of example.

For example, the plane facets 6 could be replaced by facets shaped like a frusto-conica1 portion. Also, the undulations could be continuous, without any plane portion such as parts 5, 7, though the plane parts 5 have the advantage of bearing a greater load, particularly when the shaft is not moving.

I claim:

1. A self-lubricating abutment for a shaft comprising a shaft, a porous sintered metal abutment, a bearing surface on and perpendicular to the axis of said shaft and rotating in contact with said abutment, facets on said abutment, undulations formed by said facets, the directions of the edges of the highest and lowest parts of said undulations passing through the axis of rotation of said abutment and a layer of sintered microporous metal having a porosity below 1.3/L microns covering the entire surface of said undulations.

References Cited UNITED STATES PATENTS 1,236,511 8/1917 Waring 308 2,615,766 10/1952 Wallace. 2,899,243 8/ 1959 Acterman.

FOREIGN PATENTS 770,060 3/1957 Great Britain.

OTHER REFERENCES Design of Powdered Metal Parts by W. H. Arata, published in Product Eegineering, August 1944, pp. 561 thru 564 relied upon.

MARTIN P. SCHWADRON, Primary Examiner. FRANK SUSKO, Assistant Examiner. 

